THOMAS Lauderdale started a band 21 years ago in Portland, Oregon. He had a Harvard degree and political ambitions, and had already worked for the city mayor and state governor.

Pink Martini, which the New York Times has described as a "suave salon orchestra", and – according to its musical director – plays "urban global music", began with the aim of being popular in Portland, Oregon, he says.

"It was something fun and festive to do before I ran for office. I never intended that we would travel, and if we had set out to do that it never would have worked. But I've no regrets – it has turned out to be a wonderful ride."

It is not easy to encapsulate exactly what Pink Martini do, but Lauderdale's arranging skills have serviced jazz standards, cabaret hits, pop music harvested from around the world and tunes from the golden age of Holywood. The band features eleven top instrumentalists, and embraces other ensembles along the way – notably the Scottish Chamber Orchestra on a previous visit to Scotland – and has regular vocal partners in China Forbes (who is with them again when Pink Martini plays Glasgow at the end of the month), Storm Large and Al Shapiro, as well as less frequent liaisons with the von Trapps – great-grandchildren of the family immortalised in The Sound of Music – and Rufus Wainwright.

Lauderdale also finds time to lend his own talents elsewhere. The day after Pink Martini's UK tour ends, he'll be at the piano in the Royal Festival Hall for Meow Meow's Pandemonium show with the London Philharmonic Orchestra, a one-off that follow's the cabaret artiste's summer of Weimar music with Barry Humphries and role as Titania in A Midsummer Night's Dream at Shakespeare's Globe.

But the entire globe is now Pink Martini's prairie oyster, or at least all of North America and Europe.

"The summer is a good time to travel, don't you think?" asked the musical director when we spoke, and he was on the point of leaving London for a long list of dates in France. "And we now have an audience on both continents. In fact we had a career in Europe before the US, and had played 150 dates in France over the years."

That early popularity led to a Pink Martini tune, Sympathique, being used in a French car advertisement, and the revenue from that made the down payment on the building in Portland that is its base, housing rehearsal studio, label office, music library and Lauderdale's apartment. But from there Pink Martini speaks to the world, with a repertoire of songs that requires its singers to master Arabic, Portuguese, French, Russian, Armenian and Xhosa, as well as English.

"Hopefully there is some cohesion, but every city we visit we scour the independent record stores for records that just look interesting."

The result is a basket of music that reflects the travels of Pink Martini as well as Lauderdale's insatiable musical curiosity, and has become something of an obsession.

"I feel we can't go back to Bucharest without a song in our book that we collected form there."

Lauderdale also has a contact book of the finest players to keep Pink Martini functioning in peak trim. "There is so much electronics now, and it may be old fashioned, but we are going in the opposite direction, with real people playing real instruments."

The UK leg of Pink Martini's 21st birthday tour comes a month before the release of a new album, entitled Je Dis Oui, which is likely to resonate with the band's friends in the northern arm of the Auld Alliance. It features Rufus Wainwright among its cast of singers, but Lauderdale has an eye to an older generation for possible future collaborators. Asked to cite people he'd like to work with, he rhymes off a list of veterans he knows are still working, some of whom he has actually made appointments to see. They include Juliet Greco, 89 and with a new album, Merci, out just last year, Doris Day, 92, Dame Vera Lynn, 99, whose Now is the Hour the band has reworked, Dick Van Dyke, 90, whose repertoire has lent them Hushabye Mountain, and Nana Mouskouri, a mere youngster at 81. Loretta Lynn, 84, and Dolly Parton, just 70, are also on his ever-so-slightly camp wishlist as well.

But although he is being playful, there is now a seriousness about the work of Pink Martini that you sense almost surprises the bandleader himself.

"Yes, it started out camp but it has become less so. Camp can only go so far, and we are more earnest now. In these times it didn't feel right to always have a smirk on one's face."

Pink Martini play Glasgow Royal Concert Hall on October 27.